Commit a2b4da95 authored by Lucas De Marchi's avatar Lucas De Marchi
Browse files

drm/xe: Refactor mmio setup for multi-tile 



Extract functions to setup the multi-tile mmio space and extension
space, while better documenting the final memory layout.  No change in
behavior.

Reviewed-by: default avatarGustavo Sousa <gustavo.sousa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240723045558.288693-1-lucas.demarchi@intel.com


Signed-off-by: default avatarLucas De Marchi <lucas.demarchi@intel.com>
parent 6482253e

drivers/gpu/drm/xe/xe_mmio.c

+77 −22
Original line number Diff line number Diff line
@@ -33,29 +33,56 @@ static void tiles_fini(void *arg) 
		tile->mmio.regs = NULL;

}



int xe_mmio_probe_tiles(struct xe_device *xe)

/*

 * On multi-tile devices, partition the BAR space for MMIO on each tile,

 * possibly accounting for register override on the number of tiles available.

 * Resulting memory layout is like below:

 *

 * .----------------------. <- tile_count * tile_mmio_size

 * |         ....         |

 * |----------------------| <- 2 * tile_mmio_size

 * |   tile1->mmio.regs   |

 * |----------------------| <- 1 * tile_mmio_size

 * |   tile0->mmio.regs   |

 * '----------------------' <- 0MB

 */

static void mmio_multi_tile_setup(struct xe_device *xe, size_t tile_mmio_size)

{

	size_t tile_mmio_size = SZ_16M, tile_mmio_ext_size = xe->info.tile_mmio_ext_size;

	u8 id, tile_count = xe->info.tile_count;

	struct xe_gt *gt = xe_root_mmio_gt(xe);

	struct xe_tile *tile;

	void __iomem *regs;

	u32 mtcfg;

	u8 id;



	if (tile_count == 1)

		goto add_mmio_ext;

	/*

	 * Nothing to be done as tile 0 has already been setup earlier with the

	 * entire BAR mapped - see xe_mmio_init()

	 */

	if (xe->info.tile_count == 1)

		return;



	/* Possibly override number of tile based on configuration register */

	if (!xe->info.skip_mtcfg) {

		struct xe_gt *gt = xe_root_mmio_gt(xe);

		u8 tile_count;

		u32 mtcfg;



		/*

		 * Although the per-tile mmio regs are not yet initialized, this

		 * is fine as it's going to the root gt, that's guaranteed to be

		 * initialized earlier in xe_mmio_init()

		 */

		mtcfg = xe_mmio_read64_2x32(gt, XEHP_MTCFG_ADDR);

		tile_count = REG_FIELD_GET(TILE_COUNT, mtcfg) + 1;



		if (tile_count < xe->info.tile_count) {

			drm_info(&xe->drm, "tile_count: %d, reduced_tile_count %d\n",

					xe->info.tile_count, tile_count);

			xe->info.tile_count = tile_count;



			/*

			 * FIXME: Needs some work for standalone media, but should be impossible

			 * with multi-tile for now.

			 * FIXME: Needs some work for standalone media, but

			 * should be impossible with multi-tile for now:

			 * multi-tile platform with standalone media doesn't

			 * exist

			 */

			xe->info.gt_count = xe->info.tile_count;

		}
@@ -67,24 +94,52 @@ int xe_mmio_probe_tiles(struct xe_device *xe) 
		tile->mmio.regs = regs;

		regs += tile_mmio_size;

	}

}



add_mmio_ext:

/*

	 * By design, there's a contiguous multi-tile MMIO space (16MB hard coded per tile).

	 * When supported, there could be an additional contiguous multi-tile MMIO extension

	 * space ON TOP of it, and hence the necessity for distinguished MMIO spaces.

 * On top of all the multi-tile MMIO space there can be a platform-dependent

 * extension for each tile, resulting in a layout like below:

 *

 * .----------------------. <- ext_base + tile_count * tile_mmio_ext_size

 * |         ....         |

 * |----------------------| <- ext_base + 2 * tile_mmio_ext_size

 * | tile1->mmio_ext.regs |

 * |----------------------| <- ext_base + 1 * tile_mmio_ext_size

 * | tile0->mmio_ext.regs |

 * |======================| <- ext_base = tile_count * tile_mmio_size

 * |                      |

 * |       mmio.regs      |

 * |                      |

 * '----------------------' <- 0MB

 *

 * Set up the tile[]->mmio_ext pointers/sizes.

 */

	if (xe->info.has_mmio_ext) {

		regs = xe->mmio.regs + tile_mmio_size * tile_count;

static void mmio_extension_setup(struct xe_device *xe, size_t tile_mmio_size,

				 size_t tile_mmio_ext_size)

{

	struct xe_tile *tile;

	void __iomem *regs;

	u8 id;



	if (!xe->info.has_mmio_ext)

		return;



	regs = xe->mmio.regs + tile_mmio_size * xe->info.tile_count;

	for_each_tile(tile, xe, id) {

		tile->mmio_ext.size = tile_mmio_ext_size;

		tile->mmio_ext.regs = regs;



		regs += tile_mmio_ext_size;

	}

}



int xe_mmio_probe_tiles(struct xe_device *xe)

{

	size_t tile_mmio_size = SZ_16M;

	size_t tile_mmio_ext_size = xe->info.tile_mmio_ext_size;



	mmio_multi_tile_setup(xe, tile_mmio_size);

	mmio_extension_setup(xe, tile_mmio_size, tile_mmio_ext_size);



	return devm_add_action_or_reset(xe->drm.dev, tiles_fini, xe);

}